Axiom Home Page Forums General Discussion Advice from Axiom Owners Arcam AVR600

But, but, but John, how can you so easily blow of all that expensive marketing hype? We're paying for that too!

Having recently added a pro amp for two channel listening I will toss my opinion in. I think JohnK is 100% correct, up to a volume level. Having read those blind test, I can't tell if volume was ever made part of the test. I have found over the last few weeks (perhaps 20 hr of critical listening) that that level is much lower than I originally thought. Compared to my Denon 3300's internal amp (110 w/p FTC), the pro amp is capable of offering over 3 times the power (500+ w/c). While top end volume is clearly different [well, I have not found the "TOP"], there is more mid-bass even at the upper end of the normal (for me) volume range; before you get to really loud, 100 db constant.

To try to put this into context, I'm getting better mid-bass and bass at 93 - 97dbs than I was getting at the same volume from the Denon. [Heck, I'm even getting some driver over-extension at my normal volumes, which never happened before!] I think the dynamic peaks at this volume just jumped higher than the Denon could reach while driving the other frequencies, so it clipped them and thus reduced the power hunger bass notes. BUT - the newer Denon's seem to have stronger amp sections than my 3300, maybe this is not an issue now?
So I agree all well designed amps sound the same, but that extra power is more handy than I thought as dynamic peaks must be more demanding than I gave them credit for. Alan has a good article on the amounts of power needed to reach dynamic peaks, and that seems to be what I am experiencing. If you never see 95 on the meter, a new amp would likely go unnoticed as the amps will sound the same until you exceed the current amp's unclipped range.

Hi Zimm -

Interesting take. Matches up well with what Axiom is saying about clipping. I looked at the A1400-8, which would seem to have more than enough power for my setup (M22s, VP150, QS4s and EP175 -- soon to be replaced by 2 EP400s), but am a little spooked by reports of its interaction with Audyssey:

http://www.merakspeakers.com/boards/ubbthreads.php?ubb=showflat&Number=200093

Perhaps there is such a thing as two much power?

Mind sharing which amp you picked, along with any particular features you found interesting? If/when I do get a new amp, would like to continue to use my Denon 3808 as a processor only via its pre-outs. I really like what Audyssey EQ does for my room, and Audyssey Volume Control is the best tool ever invented for selling a spouse on getting new a/v equipment.

Thanks!

Glenn

Hooky, you might want to read Ian's answer to the whole "Audyssey issue".
http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Main=14792&Number=212789#Post212789

With the A1400-8 you won't need to use Audyssey anyway. When I ran the A1400 with my M22s it made them sound like Audyssey does, more open and airy, YMMV.

So audyssey is psychosomatic too, huh?

<runs away>

Who you you calling psycho?

I dunno. I have a bunch of amps ranging from 5 wpc in Single End Triode mode into 8 ohms, to my Big Mammie Yammie, the Yamaha M-80 rated at 250 watts continuous power per channel 20Hz-20kHz at 0.003% THD (380 watts dynamic power (1kHz 8ohm)). Some of my other favorites are the wonderful Kenwood flagship KA-9100 rated at 90 or 100 wpc (and if you think your Sony AVR rated at 100 wpc pushes the same kind of watts, well... you're wrong. The KA-9100's watts are BIG WATTS.)

As much mid bass as the M22s can produce the Kenwood gets. The Kenwood driving the Michaura M66s (2 x 6.5" Axiom drivers and 1 3/4" axiom titanium tweeter) produces drop to your knees and weep for the beautiful mid bass. The Yamaha M80s drive the Thiel CS 3.6s (M80s put out 330 continuous wpc into 4ohm, 480 wpc dynamic and are stable driving 2 ohm loads) . Can't ask for better mid bass than that combo produces.

I had a Kenwood MX1000 amplifier, but got rid of that because I didn't like the sound quality it produced.

Of course, my $20 T-Amp (modded of course, hooked to a big Pyramid 3 ampere power supply) does excellent work, but lacks a bit in the mid bass.

Anyway, best mid bass? The 5 watt per channel Single end triode tube amplifier. Of course, I don't ask them to drive any load more difficult than my Dahlquist DQM 905's which are 87db efficient, 8 ohm loads.

But then, you've always been one for hyperbole.

Not at all. I bought a Crown XLS 402, but swapped it for a QSC GX5. The GX5 is a Class H amp , and makes over 500 watts (850 on one channel at 4 ohms ) at less than 0.05% THD for under $500. I am still waiting for the big "surprise" where it fails my needs miserably because it is not an audiophile amp - but so far it is more than I could have ever hoped for in my modest HT.

It is hard to figure why "audiophile" amps cost thousands more while "professional" amps often cost much less when comparing watts to watts. Companies like QSC, Crown, and others, crank out more amps per hour than many audiophile companies build in a year, so all the R&D and reliability issues are well covered. (And they operate happily at 2 ohms, so no worries of crashes with a near-4 ohm load. )

The major difference I can see is that pro amps use loud fans and audiophile amps use large, but silent, fins for heat dissipation. Some cost certainly goes there and bigger boxes become needed. (The GX5 is thinner than my CD player! But I had to crack the top and unplug the internal fan. ) The other difference is lower THD and other figures. Many informed souls on this cite say those numbers are virtually meaningless once you get below a certain threshold - I think Alan's articles says .2% is about the max to look for in THD. The Crown XLS I tried had higher THD and lower S/N and you could tell in quiet spots.

New amps, like the Axiom, take things to a whole new level where heat is not an issue, power is out of this world, and distortion and other anomalies to the signal are all but nonexistent. Given the competition, the Axiom is a bargain watt for watt. If a $4,000 amp was in my shopping cart it would be an easy pick.

As for the pro amps, I like the QSC because: (1)high, high, high power; (2) clean enough for me; (3) QSC is well respected and builds THX certified amps for real Theaters; (4) 4 ohms is no problem (5) unbalanced inputs, which is rare on pro amps; (6) a 6 year warranty; (7) nice enough looks for my HT Gx5; (8) wide availability and easy repair locations; (9) wider market if I want to sell it - good for live bands, DJs, or budding audiophiles; and (10) walked out the store with it for $350 on sale! I guess No. 10 should be No. 1 as it is the real driver.